Piston for an internal combustion engine

ABSTRACT

The piston has a lowermost ring-receiving groove formed adjacent the inner end of its bottom side with an annular oil-receiving trough. Oil removed from the cylinder wall by the piston ring during the down stroke of the piston is directed into the trough. A series of vertically extended circumferentially spaced holes in the trough function as drain holes for conveying the oil from the trough to the interior of the piston in response to the change in the directional travel of the piston on the completion of its downstroke travel.

United States Patent 1,737,658 12/1929 Howe 92/160 FOREIGN PATENTS 71,375 1/1916 Switzerland 92/160 749,855 1942 Germany 92/160 Primary Examiner-Martin P. Schwadron Assistant Examiner-A. M. Ostrager Attorney-Rudolph L. Lowell ABSTRACT: The piston has a lowermost ring-receiving groove formed adjacent the inner end of its bottom side with anannular oil-receiving trough. Oil removed from the cylinder wall by the piston ring during the down stroke of the piston is directed into the trough. A series of vertically extended circumferentially spaced holes in the trough function as drain holes for conveying the oil from the trough to the interior of the piston in response to the change in the directional travel of the piston on the completion of its downstroke travel %QW %//A PISTON FOR AN INTERNAL COMBUSTION ENGINE SUMMARY OF THE INVENTION The piston embodies a built-in oil control device that is readily adapted to commercially available pistons. The usual each upstroke travel of the piston and receives oil during each 7 downstroke travel of the piston. Excess oil is thus positively and continuously removed from the cylinder wall for return to the engine crankcase without reliance on pistonblowby for such purpose. 1 a

BRIEF DESCRIPTION GI 'THE DRAWINGS FIG. 1 is a side elevational view of the piston of this invention with parts broken away and shown in section to more clearly illustrate its construction;- I

FIG. 2 is a sectional view of the piston taken along the line 2 -2inFlG.l; 1

FIG. 3 is an enlarged sectional detail view of the head section of the piston showing the collection of excess oil from the cylinder wall on the downstroke travel of the piston; and

FIG. 4 is illustrated similarly, to. FIG. 3 and shows the discharge of the collected oil to the interior of the piston during its upstroke travel.

DETAILED DESCRIPTIONIGF'THE PREFERRED EMBODIMENT With reference to FIG. 1, the piston of this invention,.in-'

the lowermost groove 18 with an oil ring I9 of a usual type having top and bottom oil ring rails 20 and 21, respectively.

The groove 18 has a lower side 22and' an inner base side 23 (FIGS. 2 and 3). Formed in the lower side 22 with one wall continuous with the groove base side 23 is an annular oilreceiving trough 24 which has a width substantially equal to about one-half the radial depth of the groove 18. The depth of the trough 24 is equal to about one-half of its width. Circumferentially spaced about the trough 24and formed in the bottom thereof are drain holes 26 "which extend vertically downward through the head I! and the piston at the shoulder 14.

'open into the interior of I In the operation of the piston lILlet it be assumed that the piston is in its downstroke travel shown in FIG. 3. During this travel the lower rail 22 of the oil ring 19 is moved upwardly to a slightly spaced position above the groove bottom wall 22 by the engagement of the outer peripheral surface of the ring rails 20 and 21 with the inner peripheral surface of the associated cylinder wall 27. Excess oil on the surface of the cylinder wall is removed or scraped therefrom by the lower rir t g rail.2l and directed thereby into the trough 24 through the space formed between the groove bottom side-22and the ring rail 2!. This directing of oil from the surface of the cylinder wall 27 into the trough 24 continues duringthe full downstroke travel of the piston 10.

As the piston 10 starts its upstroke travel, as shown in FIG. 4, the oil withinth'e trough 24 is whipped outwardly from the trough throtagh the drain openings 26 and into the interior of the piston l for return to he englne crankcase (not shown).

This discharge flow of oil from the trough 24 continues over approximately the initial two-thirds ofthe upstroke travel of the pistonl0 due to the acceleration ofthe piston speed during such travel. 7 g

Excess oil from the cylinder wall 2'7 is thus positively and continuously removed for return to the engine crankcase without reliance on the usual blowby through the rings 17 and 19 for such purpose. With theuse of rings 17 having a mitered split, as shown in U.S. Pat. No. 2,569.777, piston blowby may be substantially eliminated and adesired lubrication condition obtained by varying the number and size of drain openings 26. By utilization of such controlled oil flow concurrently with the substantial elimination of piston blowby, the piston I0 is more efficiently cooled and engine efficiency is improved due to the I. A piston assembly for the cylinder of an internal combustion engine, comprising: v

a. A head section formed witha series of axially spaced peripheral ring receiving grooves;

b..th e lowermost one of said grooves formed in the lower sidewall thereof with an annular oil-receiving trough having an inner sidewall lying substantially in the plane of the base of said lowermost groove, and a bottom wall having a series of circumferentially spaced vertically extended holes conriecting said trough in fluid registration with the interior of said piston, said trough having a width equal to at least one-half the radial depth of said lowermost groove;

c. an oil ring for said lowermost groove having an outer peripheral surface in bearing engagement with the wall of I said cylinder; and V d. said oil ring, during the downstroke travel of the piston within said cylinder, acting to remove and direct oil from the wall of said, cylinder along the lower side of said lowermost groove and into said trough, with the oil in the zone of said holes being discharged through said holes and into the interior of said piston during the accelerated upstroke travel of the piston. 

1. A piston assembly for the cylinder of an internal combustion engine, comprising: a. A head section formed with a series of axially spaced peripheral ring - receiving grooves; b. the lowermost one of said grooves formed in the lower sidewall thereof with an annular oil-receiving trough having an inner sidewall lying substantially in the plane of the base of said lowermost groove, and a bottom wall having a series of circumferentially spaced vertically extended holes connecting said trough in fluid registration with the interior of said piston, said trough having a width equal to at least one-half the radial depth of said lowermost groove; c. an oil ring for said lowermost groove having an outer peripheral surface in bearing engagement with the wall of said cylinder; and d. said oil ring, during the downstroke travel of the piston within said cylinder, acting to remove and direct oil from the wall of said cylinder along the lower side of said lowermost groove and into said trough, with the oil in the zone of said holes being discharged through said holes and into the interior of said piston during the accelerated upstroke travel of the piston. 